System and method for telephonic voice authentication

ABSTRACT

A voice biometric authentication system and method. An authentication system is provided for authenticating a user of a telephonic device, comprising: a setup system for capturing and storing an authentic user voice sample; a comparison system that compares the authentic user voice sample with an inputted voice sample and generates a comparison result; and a control system for controlling access to the telephonic device, wherein the control system: analyzes the comparison result for an initial inputted voice sample received when a telephone call is initiated; and periodically analyzes comparison results for ongoing inputted voice samples received during the telephone call.

BACKGROUND OF THE INVENTION

1. Technical Field

The present invention relates generally to authenticating a person'svoice for accessing a device, and more specifically relates to acontinuous voice authentication system and method for telephonicdevices.

2. Related Art

As new telephony technologies continue to emerge, the ability toauthenticate users will become more and more important. For instance, aswireless devices become smaller, they become much easier to steal,misplace or lose. If such devices can only be utilized by authorizedusers, the owners or service providers of the devices need not beconcerned about unauthorized use. In addition to the actual devicesthemselves, the information being transmitted is also susceptible tounauthorized use. Accordingly, systems are required to ensure that anindividual receiving information over a telephone network is authorizedto receive it.

Numerous technologies exist for utilizing voice recognition toauthenticate users. For instance, U.S. Pat. No. 6,393,305 B1, “SecureWireless Communication User Identification by Voice Recognition,” issuedto Ulvinen et al., on May 21, 2002, which is hereby incorporated byreference, discloses a method of authenticating a user of a wirelessdevice using voice recognition. Similarly, U.S. Pat. No. 5,499,288,“Simultaneous Voice Recognition and Verification to Allow Access toTelephone Network Services,” issued to Hunt et al., on Mar. 12, 1996,which is hereby incorporated by reference, discloses a voice recognitionsystem for enabling access to a network by entering a spoken password.

While such prior art references address the need for authenticatingusers of telephonic systems using voice recognition, the authenticationprocesses are limited in that once a user is initially authenticated, nofurther steps are taken to ensure the validity of the user. Thus, if anunauthorized user could overcome the authentication process once (e.g.,by speaking a password in a manner to fool the system), the user wouldhave unimpeded access to use the device or the information availableover the network.

Accordingly, a need exists for a voice recognition system that providesa higher degree of authentication for users of telephonic systems.

SUMMARY OF THE INVENTION

The present invention addresses the above-mentioned problems, as well asothers, by providing a voice biometric authentication system thatcontinuously analyzes input voice samples for authenticating users of avoice based system. In a first aspect, the invention provides anauthentication system for authenticating a user of a telephonic device,comprising: a setup system for capturing and storing an authentic uservoice sample; a comparison system that compares the authentic user voicesample with an inputted voice sample and generates a comparison result;and a control system for controlling access to the telephonic device,wherein the control system: analyzes the comparison result for aninitial inputted voice sample received when a telephone call isinitiated; and periodically analyzes comparison results for ongoinginputted voice samples received during the telephone call.

In a second aspect, the invention provides an authentication system forauthenticating a plurality of users accessing a conference call,comprising: a setup system for capturing and storing an authentic voicesample for each of the plurality of users; and a control system thatcontrols user access to the conference call based on comparison resultsof inputted voice samples with the authentic voice samples, wherein thecontrol system includes: a system for analyzing the comparison resultsfor an initial inputted voice sample for a joining user when the joininguser joins the conference call; and a system for periodically analyzingcomparison results for ongoing inputted voice samples for each userduring the conference call.

In a third aspect, the invention provides a method for authenticating auser of a telephonic device, comprising: capturing and storing anauthentic voice sample for the user; initiating a telephone call on thetelephonic device; comparing an initial inputted voice sample with theauthentic voice sample; deciding whether to terminate the telephonebased on the compare step for the initial inputted voice sample;periodically comparing ongoing inputted voice samples obtained duringthe telephone call with the authentic voice sample; and deciding whetherto terminate the telephone based on the periodic compare step for theongoing inputted voice samples.

In a fourth aspect, the invention provides a method for authenticating aplurality of users accessing a conference call, comprising: capturingand storing an authentic voice sample for each user; initiating accessof a joining user to the conference call; comparing an initial inputtedvoice sample of the joining user with the authentic voice samples;deciding whether to allow access to the conference call based on thecompare step for the joining user; periodically comparing ongoinginputted voice samples for all joined users obtained during theconference call with the authentic voice samples; and deciding whetherto terminate access to the conference call for any of the joined usersbased on the periodic compare step.

In a fifth aspect, the invention provides an authentication system forauthenticating a user of a voice processing system, comprising: a setupsystem for capturing and storing an authentic user voice sample; asystem for obtaining inputted voice samples; a comparison system thatcompares the authentic user voice sample with an inputted voice sampleand generates a comparison result; and a control system for controllingaccess to a device associated with the voice processing system, whereinthe control system periodically analyzes comparison results generatedfor ongoing inputted voice samples in order to continuously controlaccess to the device.

BRIEF DESCRIPTION OF THE DRAWINGS

These and other features of this invention will be more readilyunderstood from the following detailed description of the variousaspects of the invention taken in conjunction with the accompanyingdrawings in which:

FIG. 1 depicts a telephone system having a voice biometricauthentication system in accordance with the present invention.

FIG. 2 depicts a flow diagram for authenticating a cell phone user inaccordance with the present invention.

FIG. 3 depicts a flow diagram for authenticating conference call usersin accordance with the present invention.

DETAILED DESCRIPTION OF THE INVENTION

Referring now to the drawings, FIG. 1 depicts a telephone system 10having a voice biometric authentication system (VBAS) 11 forauthenticating users of telephone system 10. Telephone system 10 maycomprise any type of telephonic device through which voice informationcan be communicated, including, e.g., a wireless or cellular phone, asatellite phone, a multi-user phone system such as a company-based phonesystem, a conference call system, a land-line based telephone, aninternet telephone, a network, etc. Note that while the invention isdescribed herein with reference to a telephone system, the biometricauthentication features and concepts described herein could be embodiedin any voice processing system. For instance, the voice biometricauthentication system of the present invention could be embedded in asmartcard that included an embedded voice biometrics reader to aurallyauthenticate the holder of the card.

Set-Up

As an initial step, VBAS 11 must first store one or more authentic voicesamples 35 that can later be used as a reference to determineauthenticity of the user. In the exemplary embodiment of FIG. 1,telephone system 10 includes a set-up system 12 having a reference voicesampler 14 for capturing and sampling one or more authentic voice inputs34 for each authorized user of the telephone system 10. Capturedauthentic voice inputs 34 are then stored as authentic voice samples 35in storage device 16. In an exemplary embodiment involving a cellularphone, authentic voice samples 35 can be captured and stored by anauthorized user by, e.g., speaking a phrase into the receiver during aset-up procedure. The digital signature of each authorized user can thenbe stored in the existing hardware of the cell phone. In anotherexemplary embodiment involving a multi-user phone system, authenticvoice samples 35 for each authorized user can be stored in a centrallocation or server utilized by the phone system (e.g., similar to avoice mail system). Obviously, any method for capturing and storingauthentic voice samples could be utilized with departing from the scopeof the invention.

Once the set-up is complete and an authentic voice sample 35 is storedfor each authorized user, any individual, or group attempting to utilizethe telephone system 10 can be authenticated. If authentication fails,access to telephone system 10 can be denied or terminated, e.g., bydenying access to a feature, by terminating the call, removing theindividual from a conference call, etc.

Authentication

In order to authenticate users, VBAS 11 includes an input voice sampler20 for receiving and sampling conversation input 36; voice biometriccomparison system 18 for comparing inputted voice samples with authenticvoice samples 35; and a control system 26 for analyzing comparisonresults 32 from voice biometric comparison system 18.

Input voice sampler 20 may include: (1) an initial voice sampler 22 forsampling an initial conversation utterance from a user, and (2) aperiodic voice sampler 24 for sampling ongoing conversation input fromthe user. (The input voice sampler 20 may be implemented together withthe reference voice sampler 14.) The initial conversation utterance cancomprise any initial voice input, such as the first few words spoken bythe user, or a code word or phrase spoken by the user. Ongoingconversation input generally comprises aural information spoken by theuser during the lifetime of the conversation. Periodic voice sampler 24can collect input voice samples at any interval, or in any manner, e.g.,every N seconds, each time the user speaks, etc.

After an input voice sample is collected, it is passed to voicebiometric comparison system 18. Generally, each voice has its own uniquesignature measurable in frequency and amplitude. Voice biometricanalysis is a fairly well developed field, and techniques for comparingsignatures are known in the art. Voice biometric comparison system 18can utilize any known or later developed mechanism, system or algorithmfor comparing the input voice sample of the user with the authenticvoice sample(s) 35 saved in storage 16. In the exemplary embodiment,voice biometric comparison system 18 generates comparison results 32 foreach compare. Comparison results 32 can comprise any type of informationthat reflects the analytical results of comparing two voice samples.Possible result formats may include a binary outcome such as “match” or“no-match”; a raw score indicating a probability of a match, such as“70% match”; an error condition, such as “invalid sample”; etc.

Comparison results 32 are forwarded to control system 26. Control system26 includes an analysis system 28 that examines the comparison results32 and either allows the call to proceed or terminates the call (ordenies access to the call) using termination system 30. An importantaspect of the invention is the fact that authentication of the user iscontinuous. Specifically, because the control system 26 receives ongoingor periodic comparison results 32 for the accessing user, the controlsystem 26 is able to terminate access to the system 10 at any timeduring the conversation. Thus, while an unauthorized user may be able totrick the system to gain initial access, ongoing access can beterminated at any time during the call if one of the ongoing inputtedvoice samples fails to match one of the authentic voice samples 35.

Analysis system 28 may include various modules for analyzing orresponding to comparison results 32. For instance, in the case of aninitial inputted voice sample, the analysis system 28 may cause anadditional voice sample to be collected and analyzed in the event of a“no-match” situation. Alternatively, analysis system 28 may simply causeaccess to the telephone system 10 to be denied.

In the case of ongoing inputted voice samples, analysis system 28 maycollect and analyze multiple, or a series of, comparison results 32.Thus, the analysis system 28 can achieve a much higher level ofconfidence in authenticating a user. For instance, analysis system 28could average probability scores for a set of comparison results 32. Theaverage could then be compared to a threshold value to determine whetheror not to terminate access.

Assume an average probability score of 0.75 is required to maintainaccess to telephone system 10, and voice comparison system 18 generateda set of comparison results 32 for five sequential inputted voicesamples as follow: R1=0.7, R2=0.6, R3=0.9, R4=0.9, and R5=0.9. Theaverage value would be 0.8, which would pass the threshold of 0.75,indicating a “match” situation. Note however that if only result R1 orR2 were used, a “no-match” situation would arise, potentially resultingin an unwarranted denial of access. It should be recognized that anyalgorithm or system for analyzing a set or series of comparison resultscould be utilized without departing from the scope of the invention.

FIG. 2 depicts a flow diagram for a method of making a telephone callfrom a cell phone utilizing the principals of the present invention. Itis assumed that the cell phone has already been through the set-upprocedure and an authorized voice sample has been stored. At step S1,the call is initiated. Next, at step S2, an initial voice sample isinputted into the receiver of the phone. At step S3, the initial voicesample is compared to the authorized voice sample and access is deniedat step S4 if they do not match. If they do match, access to the cellphone is allowed, and the conversation begins at step S5.

During the conversation an ongoing voice sample is obtained at step S6.At step S7, the ongoing voice sample is compared to the authorized voicesample. If a match does not exist, further access is terminated at stepS8. Otherwise, logic flows back to step S6, where the sample and testprocedures of steps S6 and S7 are continuously repeated during theconversation. Accordingly, a continuous authorization process isprovided.

FIG. 3 depicts a flow diagram for a method of making an N-way conferencecall utilizing the principals of the present invention. It is assumedthat the phone system has already been through the set-up procedure andeach of N authorized voice samples have been stored. At step S10, theN-way call is started, and an input voice sample #1 for the firstparticipant is captured at step S11. At step S12, a test occurs todetermine if input voice sample #1 matches one of the authorized voicesamples. If no match is found, access for the first participant isterminated at step S13. If a match is found, the first participant isallowed access to the conference call at step S14.

Next, at step S15, an input voice sample #n is captured for the nthparticipant. At step S16, a test occurs to determine if input voicesample #n matches one of the authorized voice samples. If no match isfound, access for the nth participant is terminated at step S17. If amatch is found, the nth participant is allowed access to the conferencecall at step S18. Subsequently, the logic continuously repeats for eachof the n participants to ensure that each is an authorized participantthroughout the course of the conference call, thus providing continuoustesting throughout the conference call.

It is understood that the systems, functions, mechanisms, methods, andmodules described herein can be implemented in hardware, software, or acombination of hardware and software. They may be implemented by anytype of computer system or other apparatus adapted for carrying out themethods described herein. A typical combination of hardware and softwarecould be a general-purpose computer system with a computer program that,when loaded and executed, controls the computer system such that itcarries out the methods described herein. Alternatively, a specific usecomputer, containing specialized hardware for carrying out one or moreof the functional tasks of the invention could be utilized. The presentinvention can also be embedded in a computer program product, whichcomprises all the features enabling the implementation of the methodsand functions described herein, and which—when loaded in a computersystem—is able to carry out these methods and functions. Computerprogram, software program, program, program product, or software, in thepresent context mean any expression, in any language, code or notation,of a set of instructions intended to cause a system having aninformation processing capability to perform a particular functioneither directly or after either or both of the following: (a) conversionto another language, code or notation; and/or (b) reproduction in adifferent material form.

The foregoing description of the preferred embodiments of the inventionhas been presented for purposes of illustration and description. Theyare not intended to be exhaustive or to limit the invention to theprecise form disclosed, and obviously many modifications and variationsare possible in light of the above teachings. Such modifications andvariations that are apparent to a person skilled in the art are intendedto be included within the scope of this invention as defined by theaccompanying claims.

1. An authentication system for authenticating a user of a telephonicdevice, comprising: a setup system for capturing and storing anauthentic user voice sample; a comparison system that compares theauthentic user voice sample with an inputted voice sample and generatesa comparison result; and a control system for controlling access to thetelephonic device, wherein the control system: analyzes the comparisonresult for an initial inputted voice sample received when a telephonecall is initiated; and periodically analyzes comparison results forongoing inputted voice samples received during the telephone call. 2.The authentication system of claim 1, wherein the control systemterminates the telephone call if the authentic user voice sample doesnot match the initial inputted voice sample.
 3. The authenticationsystem of claim 2, wherein the control system terminates the telephonecall if the authentic user voice sample does not match an ongoinginputted voice sample.
 4. The authentication system of claim 1, whereinthe control system analyzes comparison results for a plurality ofongoing inputted voice samples in order to determine if the telephonecall should be terminated.
 5. The authentication system of claim 1,wherein the telephonic device is a portable phone.
 6. The authenticationsystem of claim 1, wherein the telephonic device comprises a system thatprovides access to a conference call.
 7. An authentication system forauthenticating a plurality of users accessing a conference call,comprising: a setup system for capturing and storing an authentic voicesample for each of the plurality of users; and a control system thatcontrols user access to the conference call based on comparison resultsof inputted voice samples with the authentic voice samples, wherein thecontrol system includes: a system for analyzing the comparison resultsfor an initial inputted voice sample for a joining user when the joininguser joins the conference call; and a system for periodically analyzingcomparison results for ongoing inputted voice samples for each userduring the conference call.
 8. The authentication system of claim 7,wherein the control system terminates the denies access to theconference call for the joining user if the initial inputted voicesample does not match one of the authentic voice samples.
 9. Theauthentication system of claim 8, wherein the control system terminatesthe access to the conference call if an ongoing inputted voice sampledoes not match one of the authentic voice samples.
 10. Theauthentication system of claim 1, wherein the control system includes asystem for analyzing comparison results for a plurality of ongoinginputted voice samples for a user in order to determine access to theconference call should be terminated.
 11. A method for authenticating auser of a telephonic device, comprising: capturing and storing anauthentic voice sample for the user; initiating a telephone call on thetelephonic device; comparing an initial inputted voice sample with theauthentic voice sample; deciding whether to terminate the telephonebased on the compare step for the initial inputted voice sample;periodically comparing ongoing inputted voice samples obtained duringthe telephone call with the authentic voice sample; and deciding whetherto terminate the telephone based on the periodic compare step for theongoing inputted voice samples.
 12. The method of claim 11, wherein thestep of deciding whether to terminate the telephone call based on thecompare step for the initial inputted voice sample includes the step of:terminating the telephone call if the initial inputted voice sample doesnot match the authentic voice sample.
 13. The method of claim 11,wherein the step of deciding whether to terminate the telephone callbased on the periodic compare step for the ongoing inputted voicesamples includes the step of: terminating the telephone call if one ofthe ongoing inputted voice samples does not match the authentic voicesample.
 14. The method of claim 11, wherein the step of deciding whetherto terminate the telephone call based on the periodic compare step forthe ongoing inputted voice samples includes the steps of: analyzingcomparison results for a plurality of ongoing inputted voice samples;and terminating the telephone call if multiple ongoing inputted voicesamples do not match the authentic voice sample.
 15. A method forauthenticating a plurality of users accessing a conference call,comprising: capturing and storing an authentic voice sample for eachuser; initiating access of a joining user to the conference call;comparing an initial inputted voice sample of the joining user with theauthentic voice samples; deciding whether to allow access to theconference call based on the compare step for the joining user;periodically comparing ongoing inputted voice samples for all joinedusers obtained during the conference call with the authentic voicesamples; and deciding whether to terminate access to the conference callfor any of the joined users based on the periodic compare step.
 16. Themethod of claim 15, wherein the step of deciding whether to allow accessto the conference call based on the compare step for the initialinputted voice sample includes the step of: denying access to theconference call if the initial inputted voice sample does not match oneof the authentic voice samples.
 17. The method of claim 16, wherein thestep of deciding whether to terminate access to the conference callbased on the periodic compare step for any joined users includes thestep of: terminating the conference call for a joined used if one of theongoing inputted voice samples of the joined user does not match one ofthe authentic voice samples.
 18. The method of claim 16, wherein thestep of deciding whether to terminate access to the conference callbased on the periodic compare step for any joined users includes thestep of: analyzing comparison results for a plurality of ongoinginputted voice samples for a joined user; and terminating access to theconference call for the joined user if multiple ongoing inputted voicesamples do not match one of the authentic voice samples.
 19. Anauthentication system for authenticating a user of a voice processingsystem, comprising: a setup system for capturing and storing anauthentic user voice sample; a system for obtaining inputted voicesamples; a comparison system that compares the authentic user voicesample with an inputted voice sample and generates a comparison result;and a control system for controlling access to a device associated withthe voice processing system, wherein the control system periodicallyanalyzes comparison results generated for ongoing inputted voice samplesin order to continuously control access to the device.
 20. Theauthentication system of claim 19, wherein the device is selected fromthe group consisting of: a smart card, a wireless phone, and a phonesystem.
 21. The authentication system of claim 19, wherein the controlsystem collects and analyzes a series of comparison results for aplurality of periodically inputted voice samples in order to controlaccess to the device.